Influenza-like illness (ILI) definitions have been used worldwide for influenza surveillance. These different case definitions can vary with regard to sensitivity and predictive values for laboratory confirmed influenza. The literature has indicated the inclusion of other viruses may be the cause of these variable results. The objective of the study was to evaluate ILI national sentinel criteria and viral etiologies in adults diagnosed with acute respiratory infection (ARI) and/or ILI from 2001 to 2003 in Sao Paulo, Brazil. Clinical and laboratory evaluations were observed from 420 adults and collected on a daily basis from outpatient care units at University Hospital. The ILI definition included: fever plus at least one respiratory symptom (cough and/or sore throat) and one constitutional symptom (headache, malaise, myalgia, sweat or chills, or fatigue). DFA and RT-PCR for influenza, parainfluenza, respiratory syncytial virus, adenovirus, enterovirus, coronavirus, rhinovirus, and metapneumovirus were performed on nasal washes and 61.8% resulted positive. The respiratory viruses detected most often were influenza and rhinovirus. ILI was reported for 240/420 patients (57.1%), with influenza and rhinovirus etiologies accounting for 30.9% and 19.6%, respectively. Rhinovirus peak activity was concurrent with the influenza season. These findings highlight the implications of other viruses in ILI etiology and suggest that during the influenza season, this clinical overlap must be considered in the diagnosis and clinical management of patients.

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s u m m a r yObjectives: To improve our understanding of the global epidemiology of common respiratory viruses by analysing their contemporaneous incidence at multiple sites. Methods: 2010-2015 incidence data for influenza A (IAV), influenza B (IBV), respiratory syncytial (RSV) and parainfluenza (PIV) virus infections were collected from 18 sites (14 countries), consisting of local ( n = 6), regional ( n = 9) and national ( n = 3) laboratories using molecular diagnostic methods. Each site submitted monthly virus incidence data, together with details of their patient populations tested and diagnostic assays used.Results: For the Northern Hemisphere temperate countries, the IAV, IBV and RSV incidence peaks were 2-6 months out of phase with those in the Southern Hemisphere, with IAV having a sharp out-of-phase difference at 6 months, whereas IBV and RSV showed more variable out-of-phase differences of 2-6 months. The tropical sites Singapore and Kuala Lumpur showed fluctuating incidence of these viruses throughout the year, whereas subtropical sites such as Hong Kong, Brisbane and Sydney showed distinctive biannual peaks for IAV but not for RSV and PIV. Conclusions: There was a notable pattern of synchrony of IAV, IBV and RSV incidence peaks globally, and within countries with multiple sampling sites (Canada, UK, Australia), despite significant distances between these sites.

Infections caused by Human Rhinoviruses (HRVs) account for 25-50% of respiratory illnesses among individuals presenting influenza-like illness (ILI). HRVs could be classified in at least three species: HRV-A, HRV-B, and HRV-C. The HRV-C species has frequently been described among children and has led to severe illness resulting in hospitalization; however, the occurrence among adults is unknown. The aim of this study was to assess the clinical presentation and species distribution of HRV infections in different populations during 2001-2008. A total of 770 samples were collected. Subjects consisted of 136 adults from the general community and 207 health-care workers (2001-2003), 232 renal-transplanted outpatients (2002-2004), 70 children with congenital heart disease (2005) and 125 children from a day-care center (2008). Amplification of HRV genes was performed by reverse transcriptase-polymerase chain reaction (RT-PCR) and followed by sequencing and phylogenetic analysis. HRV was detected in 27.4% of samples (211/770), with 72 children (36.9%) and 139 adults infected (24.2%). A total of 89.61% (138/154) unknown HRV strains were sequenced, and 79.22% (122/138) were analyzed. We identified 74 isolates (60.7%) of the HRV A species, 21 (17.2%) of the HRV B species and 27 isolates (22.1%) of the HRV C species. HRV species A and B caused ILI among adult patients, whereas HRV-C did not. The dynamics of infection among different species deserve further analysis.

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Introduction: Human adenoviruses (HAdV) play an important role in the aetiology of severe acute lower respiratory infection, especially in immunocompromised individuals. The aim of the present study was to detect HAdV using two different methods, direct fluorescence assay (DFA) and nested polymerase chain reaction (nested PCR), in samples collected from patients with acute respiratory infection (ARI) within 7 days of symptom onset. Methods: Samples (n=643) were collected from patients in different risk groups from 2001 to 2010: 139 adult emergency room patients (ERP); 205 health care workers (HCW); 69 renal transplant outpatients (RTO); and 230 patients in a haematopoietic stem cell transplantation program (HSCT). Results: Adenovirus was detected in 13.2% of the 643 patients tested by DFA and/or PCR: 6/139 (4.3%) adults in the ERP group, 7/205 (3.4%) in the HCW group, 4/69 (5.8%) in the RTO group and 68/230 (29.5%) in the HSCT patient group. Nested PCR had a higher detection rate (10%) compared with the DFA test (3.8%) (p<0.001). HSCT patients exhibited a significantly higher rate of HAdV infection. Conclusions: The adenovirus detection rate of the nested PCR assay was higher than that of the DFA test. However, the use of molecular methods in routine diagnostic laboratory work should be evaluated based on the specific circumstances of individual health services.

The dynamics of dengue virus (DENV) circulation depends on serotype, genotype and lineage replacement and turnover. In São José do Rio Preto, Brazil, we observed that the L6 lineage of DENV-1 (genotype V) remained the dominant circulating lineage even after the introduction of the L1 lineage. We investigated viral fitness and immunogenicity of the L1 and L6 lineages and which factors interfered with the dynamics of DENV epidemics. The results showed a more efficient replicative fitness of L1 over L6 in mosquitoes and in human and non-human primate cell lines. Infections by the L6 lineage were associated with reduced antigenicity, weak B and T cell stimulation and weak host immune system interactions, which were associated with higher viremia. Our data, therefore, demonstrate that reduced viral immunogenicity and consequent greater viremia determined the increased epidemiological fitness of DENV-1 L6 lineage in São José do Rio Preto.